The present invention relates to a signal processing device and a method of processing a signal that are suitable to be used in a digital mixer or the like.
In a recent digital mixer, a compressor for controlling dynamics of audio signals is provided for each input/output channel. A characteristic of the compressor is determined by means of plural kinds of parameters. Thus, it lacks possibility (or realizability) that control knobs for setting these parameters are provided for every channel. For this reason, Japanese Patent Application Laid-open Publication No. 2004-012842 discloses a digital mixer (digital recorder) in which a display for adjusting a characteristic of a compressor or the like in one channel and various control knobs (operators) are provided on a panel, and the characteristic of the compressor in one selected input/output channel (referred to as a “selected channel”) is set using this display and the various control knobs. Here, a plurality of knob images respectively corresponding to various parameters are displayed on the display and one parameter can be changed continuously by operating the corresponding knob image using a pointing device.
However, skill of a user is required to appropriately set various parameters that determine the characteristic of the compressor, and therefore it is difficult for beginners to do so. For this reason, Japanese Patent Application Laid-open Publication No. 2004-012842 discloses a technique in which one kind of parameter that monotonically decreases or increases in accordance with the amount of operation of the knob image is determined as a “standard parameter” among the plural kinds of parameters and other kinds of parameters are set in conjunction with the standard parameter. Namely, a table for associating a value of the standard parameter with a value of each of the other kinds of parameters is stored in a memory, and the values of the various parameters are determined by reading out this table. For example, Japanese Patent Application Laid-open Publication No. 2004-012842 discloses a technique in which “output gain” or “threshold” of the plural kinds of parameters is determined as a standard parameter and the other kinds of parameters are changed in accordance with the standard parameter.
However, the following problems exist in the techniques described above.
First, in the techniques disclosed in Japanese Patent Application Laid-open Publication No. 2004-012842, there has been a problem that the other kinds of parameters are also fixedly determined when the standard parameter is determined. For example, in the case where the “threshold” is defined as the standard parameter, it is impossible to define a setup state of each of plural kinds of parameters with respect to a threshold value. Here, a set of a value of the standard parameter and values of the other corresponding parameters is called a “parameter set”. In the case where a plurality of parameter sets each having musical “application of meaning” such as “for guitar”, “for base” and “for drum”, for example, are to be realized by means of the techniques of Japanese Patent Application Laid-open Publication No. 2004-012842, each of the parameter sets has to be determined so that a range of a parameter value of the standard parameter for each “application of meaning” is not overlapped. Thus, it is hard to appropriately set a value of the standard parameter in accordance with any purpose. As a result, it is impossible to realize the plurality of parameter sets each having such musical “application of meaning”.
Further, in the techniques of Japanese Patent Application Laid-open Publication No. 2004-012842, when a value of the standard parameter is determined, a parameter set is determined. However, it is impossible that a part of the parameters in the determined parameter set is changed while interlocking relative to each other. Moreover, in a digital mixer in which a parameter such as a compressor for one channel selected by the user (selected channel) of a plurality of channels is set with a GUI using a large-sized display and a dedicated control knob (operator), it is required to provide the large-sized display and the dedicated control knob. It is difficult to adopt them in a general-purpose digital mixer (for amateurs, such a mixer has a small-sized structure) in view of a cost phase, a size phase and the like. On the other hand, it also lacks possibility (or realizability) that control knobs for setting a characteristic of a compressor are provided for each of input/output channels of all channel strips.